Cholesteric liquid crystals are a material with a periodic helical arrangement. When chiral axes of the cholesterol liquid crystals are aligned perpendicularly to a substrate, it is referred to as a planar structure (or a planar arrangement stable state). The planar structure has a reflective characteristic depending on a period. Furthermore, when the chiral axes of the cholesterol liquid crystals are aligned irregularly, it is referred to as a focal-conic structure (or a focal-conic arrangement stable state). The focal-conic structure has a characteristic of scattering light.
It is noted that the planar structure and the focal-conic structure are both stable states, and researchers fabricate display screens, based on the characteristics of these structures accordingly. Therefore, this type of display screen is also referred to as bi-stable cholesterol liquid crystal display screen.
Furthermore, the cholesteric liquid crystals, including other structures with stable states, were discovered by other researches in recent years. For example, the cholesteric liquid crystals have a transparent stable state with optically uniaxial crystals, and the transparent stable state is also referred to as a uniform lying helix (ULH) stable state. In other words, the cholesterol liquid crystals can exchange among the three kinds of stable states, but there is no literature to provide a driving method of the three stable states of the cholesterol liquid crystals at this time.
Furthermore, the cholesteric liquid crystals usually require a relatively high driving voltage and are difficult to apply in liquid crystal panels. In another aspect, in view of liquid crystal panels driven inactively, a relatively high switching time is required for switching the stable states of the cholesteric liquid crystals, so there is still room for improvement.
As a result, it is necessary to provide a driving method of cholesteric liquid crystals to solve the problems existing in the conventional technologies, as described above.